Jessie Mueller, who plays Carole King in “Beautiful: The Carol King Musical,” talks about her role, along with Doug McGrath, who wrote the book for the show. It tells the story of how Carole Klein, an awkward teen living in Brooklyn, became a hit songwriter. She and her husband and songwriting partner Gerry Goffin become a songwriting powerhouse, churning out hits like “One Fine Day,” “Will You Still Love Me Tomorrow,” and “The Loco-Motion.” “Beautiful” is playing at the Stephen Sondheim Theatre.